1. Field of the Invention
The present invention relates to a fuse structure and a monitoring method thereof, and more particularly, to a fuse structure including an auxiliary device configured to measuring electrical properties of a fuse element and a monitoring method thereof.
2. Description of the Prior Art
In semiconductor processes, semiconductor components tend to be influenced by all kinds of defects or impurities more easily as the components become smaller and more complicated. If a single metal link, a diode, or a MOS is broken down, the whole chip will fail. To solve this issue, fusible links such as fuses may be employed in an integrated circuit (IC) and used to be selectively blown for ensuring that the IC can work normally.
Generally speaking, fuses are connected to redundant circuits of an IC. When defects are found in the circuit, fuses can be selectively blown for repairing or replacing defective circuits. Additionally, fuses may be designed to provide programming elements, and the circuit may be programmed according to different and customized functional designs.
Fuses are roughly classified into two categories based on their operation: thermal fuse and electrical fuse (efuse). Thermal fuses can be cut by laser for forming open circuit conditions. For efuse, the open circuit condition is formed by electro-migration (EM) effect and appropriate applied current. In addition, efuses applied in semiconductor devices may include a poly efuse, a MOS capacitor anti-fuse, a diffusion fuse, a contact efuse, and a contact anti-fuse.
Generally, the condition of the fuse may be monitored by electrical resistance measurements. However, different blowing conditions of the fuse will lead to differences in resistance, and the blowing conditions cannot be judged merely by the resistance measurement result. If the resistance control standard is set too high, some of the fuses, which can actually function normally, will be judged to be abnormal, and the manufacturing yield will be influenced accordingly.